Double leg construction for derricks



Aug. 9, 1932. RAWSON 1,871,131

DOUBLE LEG CONSTRUCTION FOR DERRIGKS Filed April 23, 1930 3 Sheets-Sheetl [N VEN TOR: LESLIE A. RAwso/v,

ATTOANEX Aug. 9, 1932 L. A. RAWSON DOUBLE LEG CONSTRUCTION FOR DERRICKSFiled April 23, 1930 3 Sheets-Sheet 2 INVENTOR: LESL/E A. RA wso/v,

Aug. 9, 1932. L. A. RAWSON DOUBLE LEG CONSTRUCTION FOR DERRICKS FiledApril 23, 1950 s Sheets-Sheet 3 A r ramvf Y.

Patented Aug. 9, 1932 UNITED s'rAres an at rice LESLIE A. RAWSON, OF LOSANGELES, CALIFORNIA, ASSIGNOR TO EMSCO DERRICK & EQUIPMENT COMPANY, 015LOS ANGELES, CALIFORNIA, A CORPORATION OF CALIFORNIA DOUBLE LEGCONSTRUCTION FOR DERRICKS Application filed April 23, 1930. Serial' No.446,555.

My invention relates to a derrick such as is employed in the oilproducing industry, having permanent main legs connected to the base andcrown and removable auxiliary legs, which main and auxiliary legssupport the weight carried by the crown of the derrick. This designpermits both the main and auxiliary legs to be used during the drillingof the well and the auxiliary legs to be removed and only the main legsused during the pump ing period, at which time only relatively lightloads are imposed on the crown of the derrick. Derricks of thischaracter form part of the prior art, and the broad idea of a derrickhaving main and auxiliary legs, as outlined above, does not constitutemy pres ent invention.

In such derricks referred to, the load is proportioned on the main andauxiliary legs by a manually operable means, and due to the reliance onthe guesswork of the workman for proportioning the load it is neverknown whether or not the load'is properly distributed on the legs. Oneof the common double leg constructions provides an adjustment means inone of the legs whereby the leg may be lengthened and thus caused tocarry a part of the load of the crown. The workman usually operates thelengthening means until he thinks that the load is properly distributed.On many occasions the workmans judgment has been greatly in error, andintense strains have been placed on one of the legs to the injury of thederrick.

My invention provides a double leg construction for a derrick in whichthe main and auxiliary legs are automatically caused to carrypredetermined proportions of the load carried by the crown of thederrick; and it absolutely eliminates the human element which isinvolved in the making of the adjustments in the derricks of the priorart.

In the derrick of my invention the predetermined load which is to becarried by the main and auxiliary legs is constant through out the useof the double legs in the derrick. I 7

ferred to in the two preceding paragraphs having a means for permittingan easy installa-tion or removal of the auxiliary leg.

Other advantages of my invention and the important features will bepointed out in the following description in which two forms of myinvention are illustrated.

In the accompanying drawings,

Figure 1 is an elevational view illustrating a derrick incorporating thefeatures of my invention.

Fig. 2 is a horizontal cross section taken on the line 22 of Fig. 1.

Fig. 3 is an elevational view in section, showing a double legconstruction of my invention in which the equalizing means is in theupper end of the derrick, and illustrates the main and auxiliary legs inoperating position. v

Fig. 4 is a view similar to Fig. 3 and shows the positions of the partswhenthe auxiliary leg is removed.

Fig. 5 is an enlarged sectional view showing the equalizing means ofFig. 8.

Fig. 6 is a section taken on the line 6-6 of Fig. 5.

Fig. 7 is a section taken on the line 7-7 of Fig. 5.

Fig. 8 is a section taken on the line 88 of Fig. 5.

Fig. 9 is an elevational sectional view corresponding to Fig. 3 butshowing the form of my invention in which the equalizing means isarranged in the lower part of the derrick.

Figs. 10 and 11 are views illustrating an alternative form of theinvention.

Fig. 12 is a fragmentary sectional view taken on the line 1212 of Fig. 3showing the details of construction of the base and the screw meansemployed in the removable leg.

Referring to the drawings in detail and particularly to Figs. 1 to 8inclusive, I will describe the preferred form of my invention.

The derrick in which my inventionis incorporated has a base construction11, a crown construction 12, and a plurality of leg constructions 14.According to usual clerrick practice, there is a leg construction placedin each corner of the derrick, and each leg construction extends from acorner of the base construction 11 to a corner of the crown construction12. In view of the fact that the four leg constructions 14 areidenticalboth in construction and operation, in the ensuing descriptionI will describe the leg construction in the singular number, but it isto be understood that the description applies equally well to the otherthree leg constructions of the derrick.

Referring particularly to Figs. 3 and 4, each leg construction includesa main leg 16 which is preferably made from an angle bar and installedin the derrick with the flanges of the angle bar extending parallel tothe sides of the base construction 11 and the crown construction 12which are of rectangular shape. The lower end of the main leg 16 extendsinto a .corner member 18 of the base construction 11 and is rigidlysecured thereto by suitable bolts 19. The upper end of the main leg 16extends within a headpiece 20 of the crown construction 12, there beinga headpiece 20 arranged at each corner thereof. The headpiece 20includes a pair of upright walls 21 which extend perpendicularly to eachother and which are engaged by the flanges of the main leg 16. The mainleg 16 is held in position against the upright- Walls 21 by bolts 23which extend through vertically elongated slots 24 of the main legs 16and also through openings provided in the upright walls 21.

The construction which I have-just described includes what isordinarilyconsidered the permanent parts of the derrick. This is the constructionwhich is used not only during the drilling operations of the well but isused during pumping operations in the well. As previously mentioned, thederrick is not called upon to handle the enormous loads during pumpingoperations. which it is called upon to withstand during the drilling ofthe well. The derrick construction as described at this point is notstrong enough or rigid enough to support the load and strain imposedduring the drilling of the well, for the reason that the main legs 16are made only heavy enough to properly handle the loads imposed on thecrown construction 12 during pumping operations. During the drillingoperations of the well it ing devices 26. The lower end of the auxiliaryleg is provided with a jack means whereby it is adjustable in length.Fitted into the tubular part of the auxiliary leg 25 is a nut 27 whichthreadedly receives a screw 28. The screw 28 has a head 29 which restsin a socket 30 provided by the corner piece 18. By rotating the screw28, which is done by applying aturning bar to the head 29, the screw maybe operated, thus changing the length of the auxiliary leg 25. Placedbetween the nut 27 and the head 29 is a plurality of horseshoe-shapedshims 31 which are so placed after the adjustment has been made, inorder that they may take the load imposed on the auxiliary leg 25 andrelieve the screw 28 of this burden. A protective sleeve 33 may beprovided for enclosing the parts of the jack.

Referring to Fig. 5, the upper ends 'of the main and auxiliary legs areprovided with a semi-spherical bearing member 35 and a semi-cylindricalbearing member 36 respectively, which members may be secured to theirrespective legs by welding or any other suitable means. These bearingmembers 35 and 36 are adapted to be seated in a semispherical seat 37and a semi-cylindrical seat 38 respectively of an equalizing member orproportioning member 39. The equalizing member or proportioning member39 has an upper semi-spherical bearing face41 which seats on asemi-spherical seat 42 provided by the headpiece 20. The semi-sphericalbearing face 41 and seat 42 are generated around a point 43 which is insubstantially the same horizontal plane XX as the centers 44 and 45around which the bearing faces of the bearing members 35 and 36 aregenerated. The point 43 is the fulcrum point around which the equalizingmember or proportioning member 39 swings. The weight of the crown isapplied from the crown to the equalizing member or proportioning member39 and from the equalizing member or proportioning member 39 to the mainand auxiliary legs 16 and 25, and the load is distributed to the twolegsaccording to the respective lengths of the lever arms A and B. Itwill be seen that the relative loads carried by the two legs may bechanged by changing the relative lengths of the lever arms A and B.

For the purpose of retaining the equalizing member or proportioningmember 39 in position to be engaged by the main and auxiliary legs priorto the installation of these legs. I provide the equalizing member orproportioning member 39 with depending lugs 47 having verticallyelongated openings 48 through which a retaining bar 49 is extended, thisretaining bar 49 being held by side walls 50 of the headpiece 20. Thedepending lugs are provided with vertically elongated openings in orderthat all of the load may be transferred from the headpiece to theequalizing member or proportioning member 39 by reason of the engagementof the seat 42 and the face 41.

In Fig. 4 I illustrate the position of the parts prior to theinstallation of the auxiliary leg 25 or after it has been removed. Itwill be seen that the equalizing member or proportioning member 39 is inan extreme tilted position due to the absence of the auxiliary leg 25,and at this time a stop lug 51 formed at the outer part of theequalizing member or proportioning member 39 is in engagement with awall 52 of the headpiece 20 in order to prevent further movement of theequalizing member or proportioning member 39. V For the purpose ofexplaining the operation of the invention, let us assume that thederrick has been assembled to the point shown in Fig. 4 and that theauxiliary leg 25 is now to be installed. The jack at the lower end ofthe auxiliary leg is operated so as to shorten the leg in order that itmay be placed so that the bearing member 36 may be placed in the seat 38and the head 2-9 of the jack may be placed in the seat 30. The workmanmay then'place the holding devices 26 to prevent the auxiliary leg fromfalling from place. The jack is then operated to elongate the auxiliaryleg 25 in order that it may take its predetermined part of the loadcarried by the crown construction 12. As the jack is operated and theauxiliary leg 25 elongated, the upper end of the auxiliary leg movesupward and the bearing member 36 is brought into engagement with theseat 38 of the equalizing member or proportioning member 39. Theequalizing member or proportioning member 39 is then swung in acounter-clockwise direction, and a portion of the weight is transferredfrom the main leg to the auxiliary leg so that the two legs cooperate insupporting the load imposed on the crown of the derrick. When theauxiliary leg has been lengthened, as shown in Fig. 3, the equalizingmember or proportioning member 39 will occupy a normal position and willautomatically proportion the amount of load to be imposed on either ofthe main or auxiliary legs. During the time that this adjustment ismade, there must be a relative movement between the crown constructionand the mainlegs, and for this reason the upper ends of the main legsare provided with vertically elongated slots 24 through which the bolts23 are extended.

The equalizing member or proportioning member 39 is provided with theextensive bearing face in order that it may be fully" ing member-orproportioning member 39 will W swing around a horizontal axis on whichthe point 43 is located. The upper end of the main leg and theequalizing member or proportioning member 39 are provided withsemi-spherical hearings in order that the equalizing member orproportioning member 39 may freely adjust itself to compensate for anyslight disalignment of either of the legs. If desired, both bearingmembers 35 and 36 may be semi-spherical.

I prefer to place the equalizing member or proportioning member 39 inthe upper part of the derrick because of the fact that during theplacement or removal of the auxiliary leg 25 it is necessary only tovertically move the crown of the derrick.

The main and auxiliary legs, as shown in Fig. 3, are in the positionswhich they occupy during the drilling of the oil well when enormousstrains are imposed on the der rick. After the well has been drilled andthe pumping apparatus installed, the crown is calledupon to support therelatively light tubings which are used during pumping. At this time theauxiliary leg is removed, and the parts occupy the position shown inFig. 4. The auxiliary leg is removed by operating the jack member so asto shorten the auxil iary leg in order that the equalizingmember orproportioning member 39 may swing into the position shown in Fig. 4 sothat the entire load will be carried by the main leg 16 and so that theauxiliary leg may be conveniently removed upon detaching the devices 26.

In Fig. 9 I show a form of my invention in which the equalizing means orproportioning member is placed in the lower part of the derrick. Theupper ends of the main and auxiliary legs 16 and 25, respectively, aresecured in the headpiece 20, as shown, and may be immovable relativethereto. The lower end of the main leg 16 is provided with thevertically elongated slots 24 through which the bolts 23 are extended.The adjustment means at the lower end of the auxiliary leg 25 isprovided with the semi-cylindrical bearing 36 and engages the equalizingmember or proportioning member 39 The semi-spherical seat 42 in thisform of the invention is provided by the upper wall of the corner piece18. a

The operation of this form of my invention is identical with that of theform shown in Figs. 1 to 8 inclusive. When placing or removingtheauxiliaryleg 25, it is necessary to raise or lower the entire derrickstructure with the exception of the base construction 11, ratherthanonly the crown construction 12, as in the first formof my invention. 7

In the form of my invention shown in Figs. 10 and 11 the auxiliary leg25 is of a predetermined length and is not adjustable in length. Theequalizing member or proportioning member 39 has an ear 60 projectingoutwardly therefrom through which. a jack screw 61 is screwed. The jackscrew may be advanced through the ear 60 so as to engage the headpiece20 and to swing the equalizing member or proportioning member 39 intothe position shown in Fig. 10. The auxiliary leg 25 may then beinstalled by placing the lower end or head 29 in the seat 30 and thenswinging the upper end through the position shown in Fig. 10 intothe-position shown in Fig. 11. The jack screw is then rotated to permitthe equalizing member or proportioning member 39 to be released so thatit may swing into equalizing position, as shown in Fig. 11.

I consider my invention to be broadly novel in the provision of aderrick having a double leg construction in combination with means forautomatically imposing a predetermined proportion of the load on eachleg, in combination with means permitting an easy installation orremoval of the auxiliary leg.

My invention is further novel in the provision of the lengthening means,and as an alternative the jack screw 61, in the combination whereby theauxiliary leg may be removed and replaced and suitably adjusted toposition the equalizing member or proportioning member 39 in the mostdesired position.

I fully understand that various modifications and changes inconstruction may be made to suit different conditions, and having thisin mind I desire that the following claims be broadly construed and thatthe terms used therein be so construed as to include the mechanicalequivalents of the parts shown and described in this specification,which correspond to the terms used.

I claim as my invention:

1. A derrick including: an inner leg; an

- outer leg; proportioning means for automatically proportioning theload between them; and stop means for holding said proportioning meansin acertain position.

2. A derrick including: an inner leg; an outer leg; proportioning meansfor automatically proportioning the load between them; and means forlengthening one of said legs for operative engagement with saidproportioning means.

3. In a derrick, a base construction, a crown construction, a legconstruction extending between said base construction and said crownconstruction, said leg construction including a pair of legs, thecombination of: an automatic load proportioning means in operativerelation to said legs for propor tioning thereon the load carried bysaid crown construction; and stop means for holding said automatic loadproportioning means in a iven position. a

4:. In a derrick, abase construction, a crown construction, a legconstruction extending between said base construction and said crownconstruction, said leg construction including a pair of legs, thecombination of: a load proportioning means interposed in the derrickstructure through which the load carried by the crown construction istransmitted, said load proportioning means engaging said legs andproportioning the amount of :said' load carried by each of said legs;and stop means for holding said load proportioning means in a givenposition.

5. In a derrick, a base construction, a crown construction, a legconstruction extending between said base construction and said crownconstruction, said leg construction including a pair of legs, said legsbeing adapted to transmit from said crown construction to said baseconstruction the load carried by said crown construction, thecombination of: a load proportioning means supported by one of saidconstructions and fulcruming thereon, said legs engaging said'loadproportioning means on opposite sides of said fulcrum; and screw meansoperatively connected to said load proportioning and another part of thederrick for restraining said load proportioning means in non-operativeposition.

6. In a derrick the combination of: a crown construction; a primary leg;a secondary leg; load proportioning means normally engaging said legsfor distributing the load between them; and means for holding said loadproportioning means in such a position that one of said legs may beinstalled or removed.

7. In a derrick the combination of: acrown construction; a primary leg;a secondary leg; load proportioning means normally engaging said legsfor distributing the load between them; and means for adjustingthe'length of one of said legs for changing the relative position ofsaid leg and said proportioning means.

8. In a derrick the combination of: a crown construction a primary leg;a secondary leg; load proportlonlng means normally engaging said legsfor distributing the load between them and means for limiting the movement of said load proportioning means in one direction.

9. In a derrick the combination of a crown construction; a primary leg;a secondary leg; loadproportioning means normally engaging said legs fordistributing the load between them; means for limiting the movement ofsaid load proportioning means in one direction; and means for adjustingthe length of one of said legs for changing the relative position ofsaid leg and said proportioning means. 1

10. A derrick comprising: an inner leg; an

ion

outer leg; load proportioning means engaging each of said legs; and stopmeans for holding said load proportioning means in a certain position.

11. In combination with a primary leg, a secondary leg, and a thrustreceiving member of an oil well derrick: a thrust dividing deviceadapted to divide the thrust of said member and transmit it in definiteproportions to each of said legs; and means for adjusting the effectivelength of one of said legs so that said device can be made fullyoperative in the event that said leg is not initially of the properlength.

12. In combination with a primary leg, a secondary leg, and a thrustreceiving member of an oil well derrick: a thrust dividing deviceadapted to divide the thrust of said member and transmit it in definiteproportions to each of said legs; means constraining said device totransmit the entire thrust to one leg if the other leg is absent orineffective; and means for adjusting the effective length of one of saidlegs so that said device can be made fully operative in the event thatsaid leg is not not initially of the proper length.

, 13. In combination with a primary leg, a secondary leg, and a thrustreceiving member of an oil well derrick: a thrust dividing deviceadapted to divide the thrust of said member and transmit it in definiteproportions to each of said legs; and means constraining said device totransmit the entire thrust to one leg if the other leg is absent orineffective.

14. In combination with a primary leg, a secondary leg, and a thrustreceiving member of an oil well derrick: an automatic proportioningdevice fulcrumed on said member and engaged at definite lever arms oneither side of said fulcrum by said legs so that it can rock about saidfulcrum and divide said thrust in definite proportions between saidlegs; and means for limiting the amount of said rock which will occur ifone of said legs is absent or ineffective.

15. In combination with a primary leg, a secondary leg, and a thrustreceiving member of an oil Well derrick: an automatic proportioningdevice fulcrumed on said member and engaged at definite lever arms oneither side of said fulcrum by said legs so that it can rock about saidfulcrum and divide said thrust in definite proportions between saidlegs; and means for adjusting the efiective length of one of said legsso that said device will be effective if said leg is not initially ofthe proper length.

16. In combination with a primary leg, a secondary leg, and a thrustreceiving member of an oil well derrick: an automatic proportioningdevice fulcrumed on said member and engaged at definite lever arms oneither side of said fulcrum by said legs so that it can rock about saidfulcrum and divide said thrust in definite proportions between saidlegs; means for adjusting the effective length of one of said legs sothat said device will be effective if said leg is not initially of theproper length; and means for limiting the amount of said rock which willoccur if one of said legs is absent or inefi'ective.

In testimony whereof, I have hereunto set my hand at Los Angeles,California, this 11th day of April, 1930.

LESLIE A. RAWSON.

CERTIFICATE OF CORRECTION.

Patent No. 1,871,131. August 9, 1932.

LESLIE A. RAWSON.

it is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 4,line 94, claim 5, after the word "proportiening" insert the word means;and that the said Letters Patent should he read with this correctiontherein that the same may conform to the record of the case in thePatent Office.

Signed and sealed this 22nd day of November A. D. 1932.

M. J. Moore,

(Seal) Acting Commissioner of Patents.

